The present invention relates in general to priming pumps for use with a fuel delivery system. The priming pump cooperates with a base structure having a fuel inlet, a fuel outlet, and a fuel flow valve positioned partially in the base and cooperating with components of the priming pump to determine whether fuel flows through the priming pump or by-passes the priming pump.
More specifically, the present invention relates to the use of a spring-biased control knob for a priming pump, the control knob being positionable in either a locked position or a priming position. When the control knob is in the locked position, the fuel flow valve is opened and the fuel flow by-passes the priming pump and travels directly to a downstream, remote location. In this open condition, the priming pump of the present invention adds little, if any, flow restriction or what would be considered a minimum flow restriction. When priming is required or desired, the described control knob is rotated to an unlocked position and moves under a spring-biasing force to an up position. With the control knob in this position, the fuel flow valve is closed and any straight fuel flow through the base from the fuel inlet to the fuel outlet is blocked and the incoming fuel flow is redirected through the priming pump. A downward stroke of the control knob pushes the fuel within the priming pump out through the outlet opening of the base.
Current priming pumps that are used in fuel systems, excluding the present invention, are generally considered to be restrictive relative to the flow that is permitted or blocked and typically require additional systems and structures for the requisite fuel routing. Obviously, these additional requirements add both size and cost to the overall system. With the rapid development of modular fuel systems, greater attention has been directed to the need for a less restrictive, more easily operated, fuel priming pump. The priming pump of the present invention addresses these considerations in a novel and unobvious manner.